Asphalt roofing shingles are cut from a web of asphalt roofing material by cutting cylinders having knives located on the surface of the cylinder. Rubber mounting strips are mounted on the cylinders in a parallel relation to the cutting knives to strip the asphalt material from the knife after it has been cut. The mounting strips are also used to provide traction on the incoming web of asphalt material to thereby maintain a uniform length to the asphalt shingles.
The mounting strips generally consist of a metal backing strip having a series of holes throughout the length for securing the mounting strip on the cylinder. A rubber bumper is vulcanized to the suface of the metal backing strip. In practice it has been found that the ability of the mounting strip to perform its function is predicated on the reliability of the bond or adhesion of the rubber to the metal backing strip. Failure, generally, occurs either due to poor bonding of the rubber bumper to the backing strip or where the bond breaks down due to excessive stress.